1. Field of the Invention
The present teaching relates to a liquid jetting apparatus configured to jet a liquid.
2. Description of the Related Art
As a liquid jetting apparatus, an ink-jet head which jets ink has been known. The ink-jet head includes: a channel unit in which a plurality of nozzles and a plurality of pressure chambers communicating with the plurality of nozzles respectively are formed; and a piezoelectric actuator provided on the channel unit so as to cover the plurality of pressure chambers. The piezoelectric actuator has a piezoelectric layer, a plurality of individual electrodes formed on a surface of the piezoelectric layer so as to correspond to the plurality of nozzles respectively, and a common electrode facing the plurality of individual electrodes in common. In this ink-jet head, an upper surface of a vibration plate plays a role of the common electrode.
A wiring board (COF) is connected to the surface of the piezoelectric actuator. On the wiring board, a driver IC and a plurality of wires connected to the driver IC are provided. Each of the individual electrodes of the piezoelectric actuator is connected to the driver IC via the wire of the wiring board. When a drive signal is output to a certain one of the individual electrodes from the driver IC, an electric field acts on a portion of the piezoelectric layer sandwiched by this individual electrode and the common electrode (vibration plate), so that the piezoelectric layer deforms. Due to the deformation of the piezoelectric layer, a pressure is applied to the ink in the pressure chamber, so that the ink is jetted from the nozzle. In the below, for convenience of explanation, one element composed of the single individual electrode, the common electrode, and the portion of the piezoelectric layer sandwiched by the single individual electrode and the common electrode will be referred to as one piezoelectric element.
In the above-described ink-jet head, each of the individual electrodes of the piezoelectric actuator is connected to the single driver IC via each of the wires of the wiring member. Here, distances from the single driver IC to the individual electrodes of the plurality of piezoelectric elements are not equal, and a length of the wire connecting one of the individual electrodes and the driver IC is different among the plurality of piezoelectric elements. As for a piezoelectric element which is distant from the driver IC, that is, the piezoelectric element which is connected to the driver IC with a long wire, an electrical resistance of the long wire is large and accordingly, responsiveness to the drive signal output from the driver IC is deteriorated. Accordingly, behavior of the piezoelectric element varies among the plurality of piezoelectric elements, and thus, jetting characteristics, such as a jetting velocity and a jetting amount, of the liquid jetted from the nozzles also vary.